1. Field of the Invention
This invention relates to oscillating drive mechanisms, and more particularly to an oscillator drive mechanism capable of producing a mechanically varied output.
2. Description of Prior Art
Cam-driven mechanisms are commonly used in industrial applications to provide intermittent drive motion. For example, indexing and oscillating drive devices can be used to index a piecepart between work stations, to intermittently feed sheet material off a supply roll into a punch press, to operate so-called pick-and-place units for transferring workpieces from one station to another, or to mechanically retrieve selected workpieces from a series moving along a conveyor.
Such drive mechanisms utilize cams fabricated from metal or other hard materials which themselves are inherently incapable of adjustment. The output stroke or feed distance of the usual cam-driven apparatus cannot be readily adjusted without a complete changeover of the cam parts or the mechanism's other drive linkages. Thus, there has been a recurring need for an adjustable oscillator drive mechanism that results in a varied output motion while conveniently providing fixed input and output shaft locations.
One prior art attempt to overcome this problem in the context of a punch press feed operation was a gearing mechanism mounted externally of the oscillator drive to change the ultimate linear feed distance. Yet another prior art device provided linear adjustment of the drive mechanism's intermittent output motion, but had a varying output shaft location. Such a variable output shaft location feature presented problems in properly adjusting the drive components of the associated feed equipment. Still another prior art device utilized a harmonic type mechanism having relatively massive component parts which severly limited the obtainable output speeds.
It has become desirable, therefore, to have a variable oscillator drive mechanism that is comprised of lightweight components, that is able to achieve high operational speeds, that is easy to adjust and operate, and which has fixed input and output shaft locations.